Internal combustion engine



Aug. 31, 1937. MALLQRY 2,091,412

INTERNAL COMBUSTION ENGINE Filed July '7, 1936 Patented Aug. 31, 1937NITED STATES PATENT orrlce 2,091,412 INTERNAL COMBUSTION ENGINE MarionMallory, Detroit, Mich. Application July '1, 1936, Serial No. 39,441

11 Claims.

to the same crankshaft as the small cylinder (large enough in size todevelop greater power),

adapted to receive a charge of air in which fuel is admitted to it toincrease the power, the charge in the larger, cylinder being usuallyignited as a result of the electrically ignited explosion in the smallercylinder.

In the present construction, a charge suitable for idling is supplied tothe-small cylinder from a carburetor which has no valve. A charge of airfor the larger cylinder is supplied through a venturi which has an airinlet with no valve, a

metered charge of fuel being added thereto, when needed. Valve means areprovided for opening the inlet ports to the two cylinders and also aport between the two cylinders at predetermined times.

Generally speaking, the operation of the throttle neither increases nordiminishes the volume which flows into the cylinders, and the engine mayproperly be termed as a constant charged and a constant compressionengine. In the event that it is desired to have smoother performance atidle or at light loads than can possibly be had from full compression, avalve may be added, to be operated in synchronism with the throttle, toslightly reduce the air flow at idle and light load conditions. Theengine would then operate as a semi-constant compression engine, becausethe valve never completely shuts off the air. It only reduces the chargeenough to smooth out the performance. The object of the presentinvention is to improve the operation of engines of the type stated, andit differs from previous constructions in the formation and control ofthe fuel mixture supplied to the small cylinder or primary combustion 5chamber, its subsequent ignition and the propagation of the flametherefrom into the large cylinder or secondary combustion chamber.

The salient features of the invention and the advantages thereof will bemore specifically explained in connection with the accompanying drawing,in which, a Fig. 1 is a vertical sectional view taken through one of thepower units of the engine and the means for charging the same, thecompression stroke being nearly completed.

Fig. 2 shows a similar view of a modified form of charging means for thelarge cylinder.

As shown in the drawing, the engine to which the invention pertainscomprises a crank case 5, within which a crank shaftv 6 is mounted. Eachpower unit comprises a comparatively large piston I, reciprocable in thecylinder 8, and a smaller piston 9, reciprocable in the cylinder Ill.The cylinder III has a fuel mixture inlet port Ii near its lower end andat its upper end there is a primary combustion chamber II, in whichthere is a spark plug i3. At the upper end of the cylinder 8, there is asecondary combustion chamber i4, into which the flame is propagatedfromthe chamber l2 through a port IS. The chamber l3 may. also beprovided with a spark plug H5, in case dual ignition is desired. Theengine may have any number of these power units, corresponding to thenumber of cylinders in a conventional engine, but since these units areall alike, it has been deemed necessary to show only one.

The larger piston I has a connecting rod l1 formed with a bearing member18 on the crank pin IQ of the shaft 8. This bearing member has a cap 20secured by bolts or the like. The smaller piston 9 has a connecting rod2| connected to. a'pin 22 mounted in an extension 23 of the bearingmember I8.

The pistons I and 9 are shown in Fig. 1 as they are nearing the end ofthe compression stroke. At this time, both of the ports ii and ii areclosed by a sleeve valve 2|, which encircles the piston 9 within thecylinder ID. This valve, however, has

a port 25, which is adapted to uncover the port H during the latter partof the intake stroke, and a port 26 which is adapted to cover the porti5 as the engine continues its operation from the position shown in Fig.1.

The valve 24 is controlled through a connecting rod 21, which isconnected at its upper end to a lug "formed on the valve and, at itsother end, has a bearing 28 on an eccentric 30 formed on the cam shaft3!, the latter being driven from the crank shaft 6, at half the speed ofsaid shaft, by gearing shown diagrammatically at 32.

Fuel mixture is supplied to the intake port H from a manifold 33. An airinlet 34 leads through a venturi 35 to the manifold 33 and a smallcarburetor 36 supplies fuel thereto through a jet opening 31 located inthe venturi.

when the port 25 in the sleeve valve 24 registers with the port II, thepiston 9 has passed the port 2! upon the intake stroke, the port I! isclosed and there'is a high vacuum in the 0571- inder I 0.

It is to be noted that the carburetor 36, the air inlet 34' and themixture passageway there- 5 from have no valve, but are so designed thatan easily ignited mixture of proper volume and proportions for idling isdelivered to the cylinder Ill. The timing of this charge, as eflected bythe operation of the eccentric 30 and the po- 10 sition of the port I I,is or the utmost importance,

because this cylinder is so small that the velocity through thecarburetor would be slow if the carburetor were connected to an intakevalve that started to open when the piston started 5 downwardly on itsstroke. This slow velocity would fail to atomize the mixture to a pointthat would produce satisfactory idling. In the construction shown, a,high vacuum is created and stored in the cylinder l during the downward20 stroke, and, when port 25 registers with port ii, there will be ahigh velocity of the inflowing air and fuel from the nozzle 31. The fuelis, therefore, completely atomized. Also, the volume of the charge andthe proportions of the mixture are 25 substantially uniform, regardlessof the speed of operation.

The main power charge is delivered to the large cylinder 8. through theport 38 from the intake manifold 39. The inlet valve 40 is'con- 30trolled in the usual manner from the cam shaft through the rocker arm4|. It will be also understood that the exhaust from the cylinder 8' iseffected in the usual manner. The cylinder I0 is exhausted through thecylinder 8.

35 Air is supplied to the manifold 39 through a venturi 42. A carburetor43, located beneath the venturi 42 has an outlet tube 44 with" anopening 45 into the venturi. The fuel supplied through the opening 45into the air stream is 40 metered by a tapered pin 46, which is slidablein the tube 44 and is connected by a link 41 and bell crank 48 to thethrottle rod 49.

The small cylinder l0 develops just enough power for idling. For idling,thereiore, the me- 45 tering pin 48 is in its lowermost position and airalone is admitted to the cylinder 8. when more power is wanted, themetering pin is raised, admitting a progressively increasing proportionof fuel to the air stream'passing through the 60 venturi 42. v

with the construction shown in Fig. 1, the cylinder 8, as well as thecylinder Ill, operates under substantially constant compression. Thepassageway leading to the port 38 has no air 5 valve and no throttlevalve, other than the metering pin 46. Raising the metering pin servesto increase the proportion of fuel in the mixture but does not changethe volume otqthe charge. v v

60 In case the operation of the engine is rough when idling or operatingunder light loads, due to the high compression, a valve 50 may be usedin the intake passageway, as shown in Fig. 2. Thisvalveis connected by alink 5| to the up- 65 per end of the metering pin 46, so that when themetering pin is lowered to shut oi! the fuel, the valve is closed, andvice versa. It will be noted that the valve can only partly close theintake passageway, so that it only cuts oi! a part 70 of the air whenthe engine is idling. if;

' In the operation of the engine/both ports I I and I5 areclosed by thevalve 24, as stated above, during the. greater part of the intakestroke. As the piston 9 approaches the .lower end of its cyl- 75 inderon the intake stroke. the valve 24 also approaches itslowermostposition. This opens the port ll, while the port [5 remainsclosed, and the high vacuum in the cylinder I I) quickly draws in apredetermined completely atomized charge for 'idling, which is of fixedproportions and 5 volume. In the meantime, the cam shaft has caused therocker arm. 4| to open the valve 40 and a charge of air or mixture,depending upon the position of the metering pin 46, has been drawn intothe cylinder 8.

During the compression stroke, as the pistons reach the position shownin Fig. 1, the valve 24, in response to the half-speed rotation of theeccentric 30, is about to open the port l5 between the two cylinders. Itwill be noted that the small piston 9 leads thelarge piston 'I,- so thatthe compression in the chamber 2 at this time'is appreciably greaterthan in the chamber l4. As soon as the port l5 starts to open,therefore, the highly compressed mixture in the small cylinder begins torush through the port into the large cylinder. This takes place when thecompression in the small cylinder is near its maximum and before thecompression in the large cylinder has reached its maximum. This createsa high turbulence which extends to and around the spark plug I3,rendering the mixture more easily ignited. It will be understood thatthe spark occurs while turbulence is taking place.

The sleeve valve 24 is so timed and the port 26 is so disposed that theport I5 is open during the-remainder of the compression stroke andduring all of the power and exhaust strokes. The

mixture from the small cylinder is surging into the large cylinder atthe time it is ignited. This promotes flame propagation into the largecylinder. Low grade fuel may, therefore, be used for the large cylinderwith the assurance that it will be thoroughly ignited.

In fact, the high vacuum in the small cylinder at the time the port H isopened, with the resultant complete atomization of the fuel, and thehigh turbulence at the time the spark occurs, make it possible also touse low-grade fuel in the small cylinder with very good results. .Due tothe timing of-the port l5 and port ll by the sleeve valve, it can beseen that there will be no mixture passing from the large cylinder tothe small one, because the communication between the two cylinders isclosed on the intake strokes of obth pistons and it is opened at a timewhen the pressure is higher in the small cylinder than it is in thelarge one. There will be a surge from the small cylinder to the largeone,

and, by the time the large piston reaches its top 4 center, theexplosion will have taken place.

It is to be understood that the details of construction herein shown anddescribed are merely illustrative and that the invention also embracesall such-modifications as may be made within the to scope of theappended claims.

Having thus described the invention, what I claimas new and desire tosecure by Letters Patent, is:- v

l. A four cycle internal combustion engine 6 comprising two cylinders,one larger than the other, pistons reciprocable in the respectivecylinders, means including a carburetor for supplying a fixed idlingcharge to the small cylinder, means for admitting said idling charge tothe 7 small cylinder only when the piston therein is near the end of itsintake stroke, means including a second carburetor for supplying 'amixture f variable proportions to the large cylinder, means ,fordeveloping a greater compression in the small cylinder than in thelarger one and then opening communication between the two cylinders, andmeans for igniting the charge in the small cylinder and exploding itinto the large cylinder while there is a surge from the small cylinderinto the" larger one as a result of the opening of the communicationbetween them.

2. A four cycle internal combustion engine comprising two cylinders, onelarger than the other, pistons reciprocable in the respective cylinderswith the small piston leading the large one, a carburetor and venturisufficient to supply only an idling charge to the small cylinder, meansfor admitting such idling charge to the small cylinder, only when thepiston therein is near the end of its intake stroke, means for openingcommunication between the two cylinders while the pressure in the smallcylinder exceeds that in the large cylinder toward the end of thecompression'stroke, and means for igniting the charge in the smallcylinder while the mixture therein is in a turbulent state resultingfrom the opening of said communication.

3. A four cycle internal combustion engine comprising two cylinders, onelarger than the. other, pistons reciprocable in therespective cylinderswith the small piston leading the large one, means for supplying acharge of fixed volume and proportions to the small cylinder, means foropening communication .between the two cylinders while the pressure inthe small cylinder exceeds that in the large cylinder toward the end ofthe compression stroke, said communication remaining open until the endof the exhaust stroke, and

meansfor igniting the charge in the small cylinder while the mixturetherein is in a turbulent state resulting from the opening of saidcommunication.

4. A four cycle internal combustion engine comprising two cylinders, onelarger than the other, pistons reciprocable in the respective cylinders,a fuel mixture passageway with unvarying fuel and air flow capacitysuitable to supply an idling charge to the small cylinder, anindependent mixture passageway leading to the large cylinder and havingan air inlet and variable fuel inlet, means for admitting said idlingcharge to the small cylinder only when the piston therein is near theend of its intake stroke, the small piston being operable to create agreater compression in its cylinder toward the end of its compressionstroke than exists at that time in the larger cylinder, means foropening communication between the two cylinders while such pressureconditions exist, igniting the charge in the small cylinder andexploding it into the large cylinder.

5. A four cycle internal combustion engine comprising two cylinders, onelarger than the other, pistons reciprocable in the respective cylinderswith the small piston leading the large one, a fuel mixture passagewaywith unvarying fuel and air flow capacity suitable to supply an idlingcharge to the small cylinder, an independent mixture passageway leadingto the large cylinder and having an air inlet and a variable fuel inlet,means for admitting said idling charge to the small cylinder only whenthe piston therein is near the end of its intake stroke, means foropening communication between the two cylinders while the pressure inthe small cylinder exceeds that in the large cylinder toward the end ofthe compression stroke, said communication remaining open until the end01' the exhaust stroke, and means for igniting the charge in the smallcylinder while the mixture therein is in a turbulent state resultingfrom the opening of said communication.

6. A four cycle internal combustion engine comprising two cylinders, onelarger than the other, pistons reciprocable in the respective cylinders,means including a valveless carburetor and a valveless passageway tosupply a charge to the small cylinder suitable for idling, anindependent mixture passageway leading to the large cylinder and havinga constant flow air inlet and variable fuel inlet, means for admittingsaid idling charge to the small cylinder only when the piston therein isnear the end of its intake stroke, and means for igniting the charge inthe small cylinder and exploding it into the large cylinder.

and having a constant flow air inlet and variable.

fuel inlet, means for admitting said idling charge to the small cylinderonly when the piston therein is near the end of its intake stroke, meansfor opening communication between the two cylin-,

ders while the compression in the small cylinder exceeds that in thelarge cylinder toward the end of the compression stroke, saidcommunication remaining open until the end of the exhaust stroke, andmeans for igniting the charge in the small cylinder whilethe mixturetherein is in a turbulent state resulting from. the opening of saidcommunication.

8. A four cycle internal combustion engine comprising two cylinders, onelarger than the other, pistons reciprocable in the respective cylinderswith the small piston leading thelarge' remaining open until the end ofthe exhauststroke, and means for igniting the charge in the smallcylinder while it is in a turbulent state following the opening of suchcommunication between the two cylinders.

9. A four cycle internal combustion engine comprising two cylinders, onelarger than the other, with a port connecting their upper ends, pistonsreciprocable in the respective cylinders with the small piston leadingthelarge one, means to supply charges to the two cylinders from twoseparate sources, a sleeve valve disposed about the small piston withinits cylinder, means to operate said sleeve valve to admit the charge tothe small cylinder as the piston therein nears the end of its intakestroke andto close said communicat- 35 comprising two cylinders, onelarger than the 10. A four cycle internal combustion engine comprisingtwo cylinders, one larger than the other, pistons reciprocabie in therespective cylinders with the small piston leading the large one, meansfor supplying a charge of fixed volume and proportions to the smallcylinder for idling, an independent air passageway leading to the largecylinder, means for optionally admitting a metered charge of fuel tosaid passageway, and a valve on the engine side of said lastmentionedmeans and capable only of partially closing said passagewaywhen little or no fuel is being admitted to the air stream passingtherethrough.

11. A four cycle internal combustion engine other, pistons reciprocablein the respective cylinders with the small piston leading the large one,meanstor supplyi a charge of fixed volume and proportions to the smallcylinder sufllcient only for idling, a passageway leading to the largecylinder and having a. venturi with an unobstructed air inlet, a fuelnozzle opening into said venturi, a metering pin operable to close saidnozzie or to progressively open it, and a valve in said passagewayoperable in synchronism with the metering pin to shut 011 only a part ofthe air flow through said passageway when the nozzle is closed and toleave said passageway substantially unobstructed when the nozzle isopen.

' MARION MAILORY.

